Im trying to make my own ignitor, by making an arc between wires. I believe it could be done with a 9 volt battery, capacitor, and switch. Anyone know how? With a 3300 uF cap i was able to short it and make a small spark. I then added another in series and it exploded!! I guess that cap couldnt take 9volts. Unfortunatly my largest are 3300 uF and an industrial 18000 uF (which is larger than a soda can). I dont want to use the 18000 uF one mostly because of size and weight though. Should i get larger cap? Are there instructions to make an ignitor using my idea or others?

When using capacitor discharge for ignition, performance depends on the electrodes you're using. Use metals with low melting point. I used around 3200 uF @ 25V with a 9V battery and although it was enough to weld the electrodes together, it only produced a yellow-orange spark that wasn't enough to ignite the mix.Perhaps the best way to use caps is to discharge them through a step-up transformer like a car ignition coil. But then you have the issue of switching all that current...

You don't have to open it. Just solder high voltage wires to the test electrodes and make sure the gap between the electrodes in the chamber is around 0.4'' smaller than the one between the test electrodes. This should compensate for the fuel mix's higher density and prevent the spark from forming at the stun gun rather than the chamber.

I had a stun gun that wouldnt open. Easy solution: stick it in a vice. No joke. Align it so the thin sides are in the jaws of the vice. (Not the electrode and bottom sides) Then start cranking the vice. It will pop open. Just make sure to remove any screws first. They like to hide them under stickers.